📏 How Many Miles Long Is Marathon, Florida?

Marathon stretches across several islands totaling about 10 miles in length. The city is made up mainly of Vaca Key, Fat Deer Key, and Grassy Key, connected by bridges and surrounded by shimmering blue water. Because of its length, Marathon has plenty of waterfront homes, marinas, and beaches — and still keeps its friendly small-town feel. Voice Search Answer: 🎤 Marathon Florida is about 10 miles long and includes Vaca Key, Fat Deer Key, and Grassy Key. Local Tip: This 10-mile stretch offers everything — beaches, fishing, snorkeling, restaurants, and easy access to both the Gulf and Atlantic sides.